Dominoes

The double-six draw game. Match a number on either open end, draw when nothing fits, and knock when the boneyard runs dry. First player out of tiles takes the round and scores whatever everyone else is still holding.

Play the house

House rules

Double-six set, 28 tiles. Two players take 7 each, three take 6, four take 5. The rest is the boneyard.
Highest double opens the first round. After that the previous round's winner leads anything.
On your turn, match either open end. Doubles sit crosswise but still play one number.
No legal tile? Draw until you get one. Once the boneyard is empty you knock instead.
Play your last tile and the round ends. If everyone knocks in a row the round is blocked and the lowest pip count wins it.
The winner scores everyone else's remaining pips, less their own. First to the target takes the match.

Playing with friends

Open a table for two to four seats and share the room code.
Friends join with a nickname — no account needed.
Start whenever you like — two is enough. You don't have to wait for every seat, and any that are still empty can be filled by the house.
Seven tiles each, the rest to the side. Anyone who turns up after the deal takes a free seat and comes in at the next round.
Between rounds everyone readies up and the next one deals itself. Anyone with the code can watch, and spectators never see a hand.

Your tiles stay yours: hands are held on the server and only turned face up when a round is settled.